The invention relates to a heating device (1), comprising a housing (2), which has a fluid channel arranged therein, which has a fluid inlet (12, 13) and a fluid outlet (12, 13), wherein an element (30) that generates an alternating magnetic field is provided in the housing (2), which element is separated from the fluid channel in a sealed manner by at least one wall, wherein furthermore at least one metal planar heating element (3, 8, 22) is provided, which can be heated by the alternating magnetic field, wherein the at least one planar heating element (3, 8, 22) is arranged in the fluid channel, wherein at least one of the planar heating elements (3, 8) is made of a magnetic material.